Throttle stumble just after idle

Alright fellas followed 5twins direction on cam chain adjustment, and adjusted my valves which were all off either too tight or too loose and I still can’t get this thing dialed in. How junky are the carbs from mikesxs or tcbros? At this point I would take a bike that runs pretty good over barely runs. I’m starting to loose my patience with this bikes resilience and my lack of success. I’m at a total loss as to what to check and or adjust at this point.
I’ve messed with other carbs before (PWK’s) and imho, the stock carbs are much better. If you’re looking for enhanced performance others like the Mikuni VM34’s. My stock BS38’s run great.
 
In theory I could check the voltage over a couple minutes at idle with a meter and see what the capacitor is doing right? I imagine the tolerance for spikes and drops should be relatively tight? .5V-1.0V?
You could. But then what... a couple hrs research trying to interpret what you saw?
Or you could do as JP suggests, jumper in a battery and have an answer in minutes. :shrug:
 
While I attended the XS650 Society Ralley in the Ozarks, a gentleman from Kansas pointed out a little accessory he was fond of. A $10 voltagmeter wired into my headlight shell tells me what my system is seeing. Jpdevol may have brilliant insight here.
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IDK about my insight - my eyesight ain't worth shit - but that meter is bright !; even I could see that.:laugh2:
 
You could. But then what... a couple hrs research trying to interpret what you saw?
Or you could do as JP suggests, jumper in a battery and have an answer in minutes. :shrug:
So what would be the procedure for that? Bring a wire off the positive on the battery to my positive on the capacitor and leave the positive from my PMA under the terminal with the battery wire as well? Almost as a “supplemental” power source so to speak?
 
So what would be the procedure for that? Bring a wire off the positive on the battery to my positive on the capacitor and leave the positive from my PMA under the terminal with the battery wire as well? Almost as a “supplemental” power source so to speak?
That would do it. Another way would be to start the engine, warm it up until it idles nice, let it idle a minute and check your capacitor voltage. Then rev it to stumble and see if voltage goes down momentarily before rising. But the surefire way is adding a 12v supply to the capacitor. 1 battery, 2 jumper wires and you will know for certain.
 
That would do it. Another way would be to start the engine, warm it up until it idles nice, let it idle a minute and check your capacitor voltage. Then rev it to stumble and see if voltage goes down momentarily before rising. But the surefire way is adding a 12v supply to the capacitor. 1 battery, 2 jumper wires and you will know for certain.
I appreciate the knowledge my friend. I’ll be back probably Friday evening with results
 
IDK about my insight - my eyesight ain't worth shit - but that meter is bright !; even I could see that.:laugh2:
That would do it. Another way would be to start the engine, warm it up until it idles nice, let it idle a minute and check your capacitor voltage. Then rev it to stumble and see if voltage goes down momentarily before rising. But the surefire way is adding a 12v supply to the capacitor. 1 battery, 2 jumper wires and you will know for certain.
THE BATTERY SOLVES MY ISSUE AND BOY DOES THIS THING SOUND AMAZING! As soon as it started, it idled better and only needed the choke for about 5 seconds instead of a minute and ZERO throttle lag now! So now my question is, what do I do now?! If I leave a battery as I have it, connected directly to the capacitor will my PMA still charge it?
 
THE BATTERY SOLVES MY ISSUE AND BOY DOES THIS THING SOUND AMAZING! As soon as it started, it idled better and only needed the choke for about 5 seconds instead of a minute and ZERO throttle lag now! So now my question is, what do I do now?! If I leave a battery as I have it, connected directly to the capacitor will my PMA still charge it?
Best way to find out is measure the voltage at the nutters with engine running at 2500-3500 rpm. You should see 14 .4 volts but anything above ~13.8-13
9 volts is putting charge into the battery. Next, find a smaller battery to hide somewhere on your bike and do the same check. There are probably threads here about small Li batteries. If I studied up on it or remembered shit from my electronics days, a larger capacitor might do the trick. Others may chime in.
 
Yep, the capacitor isn't really needed unless you want to go with a small LiFePo battery. The PMA & regulator should be fine with the battery given the specs TW quoted. You have the space to mount a battery and do a clean looking install👍
 
Best way to find out is measure the voltage at the nutters with engine running at 2500-3500 rpm. You should see 14 .4 volts but anything above ~13.8-13
9 volts is putting charge into the battery. Next, find a smaller battery to hide somewhere on your bike and do the same check. There are probably threads here about small Li batteries. If I studied up on it or remembered shit from my electronics days, a larger capacitor might do the trick. Others may chime in.
At idle it drops to around 12.5 and does run a little choppy I guess you could say, full throttle it runs up to 15.5 V +/- I imagine maybe my idle is just a little too low to maintain a healthy voltage down low? I’m speculating at this point. Thanks guys
 
The 15.5 is too much and indicates the regulator is suspect. Idle speed 1000-1100rpm. I'd take the capacitor out of circuit and retest voltage output @ battery.
 
I'm curious to know the AC output at the stator connector ahead of the regulator (between each 3 white or yellow)
 
BTW, the output spec we're looking for is 14.5VDC @ 2000rpm and it should not increase passed that at higher rpm (4000).
We're looking for 10-15VAC @ 1100rpm from the stator
 
I'm curious to know the AC output at the stator connector ahead of the regulator (between each 3 white or yellow)
This measurement will need to be taken with the bike running correct? I haven’t opened it yet but is there a way to get my meter probe into the connector with the connectors together? Edit I just realized they won’t be together to be ahead of the regulator. So the bike will still run without the regulator in the circuit?
 
Yep connected and running. Should be able to insert probes in one side of block connector
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